1. Transcription Notes

2. Transcription Information in DNA is used to make proteins (specifically in the bases – A, T, G or C)Information in DNA is used to make proteins (specifically in the bases – A, T, G or C) DNA is found in the nucleusDNA is found in the nucleus Proteins are made in the ribosomesProteins are made in the ribosomes DNA is double-stranded and is too big to leave the nucleusDNA is double-stranded and is too big to leave the nucleus

3. How does the information on DNA get to the ribosomes? This is where RNA comes in:This is where RNA comes in: RNA = Ribonucleic acidRNA = Ribonucleic acid RNA is single-stranded, so it is smaller and can fit out of the nucleusRNA is single-stranded, so it is smaller and can fit out of the nucleus DNA’s information is copied onto mRNA (messenger RNA) and mRNA takes the message to the ribosome to make proteinsDNA’s information is copied onto mRNA (messenger RNA) and mRNA takes the message to the ribosome to make proteins

4. Definition of Transcription The process of copying DNA onto mRNA in order to get the information from the nucleus to the ribosomes to make proteinsThe process of copying DNA onto mRNA in order to get the information from the nucleus to the ribosomes to make proteins

5. Picture of Transcription Ribosomes Cell Membrane Nucleus mRNA DNA

6. RNA VS. DNA Single – StrandedSingle – Stranded Sugar – RiboseSugar – Ribose 4 Bases:4 Bases: –Adenine (A) –Guanine (G) –Cytosine (C) –Uracil (U) Double – Stranded Sugar – Deoxyribose 4 Bases: Adenine (A) Guanine (G) Cytosine (C) Thymine (T)

7. How is information copied onto mRNA? This process is similar to replicationThis process is similar to replication RNA Complementary Base Pairs are a little different than DNA Base PairsRNA Complementary Base Pairs are a little different than DNA Base Pairs – G – C – A – U (instead of T)

8. Steps of Transcription Step 1:Step 1: DNA must unwind and unzip.DNA must unwind and unzip. The weak Hydrogen bonds that hold the DNA strand together in the middle are broken by an enzyme.The weak Hydrogen bonds that hold the DNA strand together in the middle are broken by an enzyme.

9. Steps of Transcription Step 1 (Picture):Step 1 (Picture): A - T A - T T - A T - A C - G Enzyme unzips C - G Enzyme unzips G C DNA at the G C DNA at the A T WEAK A T WEAK G C hydrogen bonds G C hydrogen bonds G C G C

10. Steps of Transcription Step #2:Step #2: The DNA strand pulls apart and free RNA nucleotides (that are floating around in the nucleus) begin to pair up with their complementary nucleotide on ONE side of the DNA strand with the help of an enzyme.The DNA strand pulls apart and free RNA nucleotides (that are floating around in the nucleus) begin to pair up with their complementary nucleotide on ONE side of the DNA strand with the help of an enzyme.

11. Steps of Transcription Step #2 (Picture):Step #2 (Picture): A A - T Free RNA A A - T Free RNA T U - A nucleotides T U - A nucleotides C C - G floating in C C - G floating in G G - C the nucleus G G - C the nucleus A A - T A A - T G C G C DNA mRNA DNA DNA mRNA DNA U G G U A A C

12. Steps of Transcription Step #3:Step #3: After copying the desired section of DNA, the mRNA separates from the DNA strandAfter copying the desired section of DNA, the mRNA separates from the DNA strand The mRNA (which is single- stranded) now leaves the nucleus and goes to the ribosomes to make proteinsThe mRNA (which is single- stranded) now leaves the nucleus and goes to the ribosomes to make proteins

13. Steps of Transcription Step #3: (Picture)Step #3: (Picture) A U C mRNA single-stranded C mRNA single-stranded G A G G

14. Steps of Transcription Step #4:Step #4: The original DNA zips back together and stays in the nucleusThe original DNA zips back together and stays in the nucleus

15. Steps of Transcription Step #4 (Picture):Step #4 (Picture): A - T A - T T – A T – A C – G Original DNA strand G – C A - T G – C G – C G - C G - C

16. Transcription Animations http://www.stolaf.edu/people/gia nnini/flashanimat/molgenetics/tr anscription.swfhttp://www.stolaf.edu/people/gia nnini/flashanimat/molgenetics/tr anscription.swfhttp://www.stolaf.edu/people/gia nnini/flashanimat/molgenetics/tr anscription.swfhttp://www.stolaf.edu/people/gia nnini/flashanimat/molgenetics/tr anscription.swf http://www- class.unl.edu/biochem/gp2/m_bio logy/animation/gene/gene_a2.ht mlhttp://www- class.unl.edu/biochem/gp2/m_bio logy/animation/gene/gene_a2.ht mlhttp://www- class.unl.edu/biochem/gp2/m_bio logy/animation/gene/gene_a2.ht mlhttp://www- class.unl.edu/biochem/gp2/m_bio logy/animation/gene/gene_a2.ht ml

17. Transcription Simulation Transcription Simulation Make sure Biological Simulations CD is in the drive